Video projectors are known that employ a CRT (cathode-ray tube) or transmitting liquid crystal light valve as the source of a projected image. Also, high-definition versions of such image sources have been realized.
Unfortunately, conventional video projectors for such high-definition image sources are unsatisfactory especially due to the difficulty in achieving a desired high level of brightness and definition of the projected image using such projectors.
Video projectors have been realized that employ optically addressed spatial light modulators as a means for improving the brightness and definition of the projected image on a screen. In these systems, a video image is "written" on a liquid crystal layer by conducting an original image (formed on a CRT or analogous device) onto a spatial light modulator (SLM). Light from a light source is impinged on the liquid crystal layer "imprinted" with the image; light (containing the image) reflected from the liquid crystal layer is then projected onto a viewing screen using a projection lens.
To "write" the image on the spatial light modulator, an optical fiber array or optical relay is disposed between the image source and the spatial light modulator. Use of an optical fiber array as an image-conducting means advantageously is amenable to miniaturization. Unfortunately, however, an optical fiber array has the still unsolved problem of introducing "chicken wire" artifacts on the image and also is expensive.
Conventional optical relays can also be made small and can be used at full magnification. However, for optimal performance, the optical relay must be able to transmit a bright image in order to effectively drive the spatial light modulator. It has heretofore been very difficult to realize an optical relay that conducts a bright image and that produces high image quality at full magnification.